During his/her PhD studies, the student conducts original research work which leads to publications and oral or poster announcements in national and international scientific events such as Conferences, Workshops, and Meetings. Eventually, this research work must be written in the form of a PhD Thesis which constitutes a coherent piece of independent research that makes a solid contribution to the general pool of scholarship. The length of the thesis, the number of associated publications, and the time required to complete it depend on many factors such as the  capabilities and effort of the student, the technical and conceptual details of the specific research project, the philosophy of the thesis advisor, and many others. A minimum of one scientific publication in a peer-reviewed Journal is absolutely required for the PhD student to be allowed to defend his/her PhD thesis. The preferred language of the PhD Thesis is English.

The PhD Thesis should also be accompanied by a 15-page Synopsis. The language of the Synopsis is Greek for Greek-speaking PhD candidates and English for non-Greek speaking candidates.

Once the Thesis has been written and approved by the members of the Thesis Committee, the PhD candidate should orally defend it through a formal presentation to the department, the PhD exam committee, and the public. The PhD exam committee includes seven members: the three members of the Thesis Committee plus four additional members either from the Department or outside it. These four members are proposed by the Thesis Advisor and must be approved by the Department. The PhD thesis defense is intended to demonstrate that the student has: a) acquired the skills necessary to think creatively and critically, and hence conduct high-quality research, and b) performed original scientific work which advanced the state of knowledge in the relevant field.